<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .father{
            width: 300px;
            height: 300px;
            background-color:pink ;
        }
        .son{
            width: 100px;
            height: 100px;
            background-color: yellow;
        }
    </style>
</head>
<body>
<div class="father">
    <div class="son">
    </div>
</div>
<script>
    var father = document.querySelector('.father');
    var son = document.querySelector('.son');
    father.addEventListener('mouseenter',function () {
        console.log(11);
    });
</script>
</body>
</html>
